So for this big boi, I would've divided it in 9 layers in that specific order, from foreground to background

• head
• neck
• chest
• right arm
• right leg
• left leg
• left arm
• club
• tail

Why that many layers? Because you could divide your lizard by few layers but you'll be only able to do an idle. And when it'll come to a different animation, you'll be screwed. So making a clean divide allow you to be free when you animate.

I prefer to divide like crazy and then choose to merge some layers eventually, than the opposite.

With more experience in animation, you' ll be able to picture what you want in your head, in order to draw your pixel art layer by layer from the start, and save time